AUDAC WB45SI/FS Flush-Mount Box for a Wall Panel, Solid Wall

The WB45SI/FS is the solid-wall counterpart to AUDAC's hollow-wall boxes: it is chased into stone or concrete and gives a standard-sized product - a matrix control panel, a volume controller, a connection plate - a flush finish rather than a surface-mounted lump on the wall.

AUDAC lists it as compatible with the WP2xx series, the NWPxxx series and the NCP105. The one exception worth knowing before you cut: the NWP222 series needs two WB45SI/FS boxes joined together, not one.